According to the version of FIPS 180 available back in 2005, SHA-1 has an input length limitation, which means there are not an infinite number of messages that are valid SHA-1 inputs to begin with. The reason for this constraint is the padding contains a fixed length input bit length field.

Older algorithm of a similar design, such as MD5, also have fixed length input bit length fields in their padding, but no input length limitations. These hashes consequently have a theoretically infinite number of valid inputs.

Some newer algorithms, such as SHA-3, do not have fixed length input bit length fields in their padding, and consequently do not have any input length limitation.

According to the version of FIPS 180 available back in 2005, SHA-1 has an input length limitation, which means there are not an infinite number of messages that are valid SHA-1 inputs to begin with. The reason for this constraint is the padding contains a fixed length input bit length field.

Older algorithm of a similar design, such as MD5, also have fixed length input bit length fields in their padding, but no input length limitations. These hashes consequently have a theoretically infinite number of valid inputs.

Some newer algorithms, such as SHA-3, do not have fixed length input bit length fields in their padding, and consequently do not have any input length limitation.

According to the version of FIPS 180 available back in 2005, SHA-1 has an input length limitation, which means there are not an infinite number of messages that are valid SHA-1 inputs to begin with. The reason for this constraint is the padding contains a fixed length input bit length field.

Older algorithm of a similar design, such as MD5, also have fixed length input bit length fields in their padding, but no input length limitations. These hashes consequently have a theoretically infinite number of valid inputs.

Some newer algorithms, such as SHA-3, do not have fixed length input bit length fields in their padding, and consequently do not have any input length limitation.

According to the version of FIPS 180 available back in 2005, SHA-1 has an input length limitation, which means there are not an infinite number of messages that are valid SHA-1 inputs to begin with. The reason for this constraint is the padding contains a fixed length input bit length field.

Older algorithm of a similar design, such as MD5, also have fixed length input bit length fields in their padding, but no input length limitations. These hashes consequently have a theoretically infinite number of valid inputs.

Some newer algorithms, such as SHA-3, do not have fixed length input bit length fields in their padding, and consequently do not have any input length limitation.